This invention relates to a method and apparatus for remotely operating a circuit breaker.
Motor operators (motor charging mechanisms) allow the motor-assisted operation of electrical circuit breakers. A motor operator is typically secured to the top of a circuit breaker housing. A linkage system within the motor operator mechanically interacts with a circuit breaker operating handle, which extends from the circuit breaker housing. The linkage system is operatively connected to a motor within the motor operator. The motor drives the linkage system, which, in turn, moves the operating handle to operate the circuit breaker. The operating handle is moved between xe2x80x9conxe2x80x9d, xe2x80x9coffxe2x80x9d, and xe2x80x9cresetxe2x80x9d positions, depending on the rotational direction of the motor.
When the handle is moved to the ON position, electrical contacts within the circuit breaker are brought into contact with each other, allowing electrical current to flow through the circuit breaker. When the handle is moved to the OFF position, the electrical contacts are separated, stopping the flow of electrical current through the circuit breaker. When the handle is moved to the xe2x80x9cresetxe2x80x9d position, an operating mechanism within the circuit breaker is reset, as is necessary after the operating mechanism has tripped in response to an overcurrent condition in the electrical circuit being protected by the circuit breaker.
The motor operator must be designed to prevent damage to the circuit breaker and to itself, when moving the circuit breaker handle to these various positions. In particular, the motor operator and the circuit breaker must be designed such that the xe2x80x9covertravelxe2x80x9d of the handle past the reset position does not damage the circuit breaker operating mechanism. This is typically achieved by strengthening the motor operator and the circuit breaker so that they may withstand the stress caused by overtravel, or by use of a limit switch and solenoids to disengage the motor after the handle has reached a desired point.
While effective, the use of limit switches and solenoids to disengage the motor requires the use of many components and, therefore, increases the cost of the motor operator and its potential for failure.
A motor operator for a circuit breaker, the motor operator includes a motor drive assembly connected to a mechanical linkage system for driving an energy storage mechanism from a first state of a plurality of states to a second state of the plurality of states, each state having a prescribed amount of energy stored in the energy storage mechanism, the energy storage mechanism provides an urging force to the mechanical linkage system, the mechanical linkage system is coupled to a carriage assembly. A motor drive assembly is connected to the mechanical linkage system for driving the energy storage mechanism from a first state of said plurality of states to a second state of said plurality of states and a release mechanism disengages the motor drive assembly from the mechanical linkage system when the energy storage mechanism is driven from the first state of plurality of states to the second state and an energy release mechanism is coupled to the mechanical linkage system to release the energy stored in the energy storage mechanism. After the energy has been released from the energy storage mechanism the release mechanism reengages the motor drive assembly to the mechanical linkage system.